Method for producing rolled edge board

ABSTRACT

A METHOD AND APPARATUS FOR MAKING STRIPS OF CLOSED EDGE CORRUGATED BOARD WITH THE EDGES OF ONE FACING SHEET FOLDED AROUND THE OPEN ENDS OF THE CORRUGATED CORE CONVOLUTIONS AND SECURED TO THE OTHER FACING SHEET FROM A SHEET OF SINGLE FACED CORRUGATED BOARD, CUT INTO STRIPS.

R. L. WASHBURN E 3,579,396

METHOD FOR PRODUCING ROLLED EDGE BOARD May "18, 1971' 4 Sheets-Sheet 1 Filed Oct. 5, 1968 May 18, 1971 W R ETAL 3,579,396

METHOD FOR PRODUCING ROLLED EDGE BOARD 4 Sheets-Sheet 2 Filed Oct. 5, 1968 May 18, 1971 WABHBURN ETAL 3,579,396

METHOD FOR PRODUCING ROLLED EDGE BOARD 4 Sheets-Sheet 5 Filed, Oct. 5, 1968 III I ll 'I I I I WU I HHH LHTWI WH l NKN R. 1.. WASH BURN ET METHOD FOR PRODUCING ROLLED EDGE BOARD May 18, 1971 O 4 Sheets-Sheet 4.

Filed Oct. 5, 1968 United States Patent 3,579,396 METHOD FOR PRODUCING RULLED EDGE BOARD Robert L. Washburn, Whittier, and William J. Krnk, Fullerton, Calif., and William S. McDonald, Georgetown,

S.C., assignors to International Paper Company, New

York, N.Y.

Filed Oct. 3, 1968, Ser. No. 764,815

Int. Cl. 1531f 5/00 US. Cl. 156-202 1 Claim ABSTRACT OF THE DISCLOSURE A method and apparatus for making strips of closed edge corrugated board with the edges of one facing sheet folded around the open ends of the corrugated core convolutions and secured to the other facing sheet from a sheet of single faced corrugated board, cut into strips.

This invention relates to methods and apparatus for producing wrapped edge corrugated paperboard and, more particularly, to methods and apparatus for producing two or more strips of such wrapped edge board simultaneously.

Corrugated paperboard, made up of a core of corrugated paper with facing sheets adhesively secured to the opposite faces of the core, has a wide variety of uses for packaging. In the production of such board, the sheet which, in the board, makes up the core, or center, is passed between the mating teeth of corrugation rolls to form convolutions extending transverse of the sheet. Adhesive is applied to the crowns of the convolutions at one side of the corrugated sheet and, with such adhesive, a facing sheet is secured to such one side of the core. An adhesive is then applied to the crowns of the convolutions at the other side of the corrugated sheet and a second facing sheet is secured, with the adhesive, to such other side. The convolutions, at two of the opposite edges of the corrugated core, are open. Thus, when cut into packaging blanks and assembled for use in packaging, foreign matter, dirt, contamination, the material being packaged, and the like, can enter the open ends of the convolutions.

In the packaging of food products, the possibility of contaminents, dirt, and the like, entering the open ends of the corrugation is, of course, undesirable. Where the food product being packaged is in a liquid, or semi-liquid, state as, for example, ice cream, the liquid or semi-liquid material can enter the open ends of the convolutions. In the packaging of some products, for example, produce and poultry, it is often desirable to package the product with ice. Where ice is to be used, it is the usual practice to coat or impregnate the corrugated paperboard sheet with a water-proof material. However, even when so coated or impregnated, the water from the ice, as the ice melts, can enter the open ends of the con'volutions, cause the corrugated sheet to lose its stiffness, weaken the adhesive bond between the corrugated core and facing sheets and causes the corrugated board to come apart.

Various arrangements have been proposed and used to seal the open ends of the convolutions at the opposite edges of the corrugated board. In one such arrangement, a facing sheet, wider than the corrugated core, is ad hesively secured to one of the faces of the corrugated core so that the edges of the wider sheet extend outwardly beyond the edges of the core. These extending edges are then folded around the open ends of the convolutions and adhesively secured to the opposite face of the board thereby forming a folded edges, closing and sealing the ends of the convolutions. Thus, contamination, dirt, liquid, and the like, is prevented from entering the core. Preferably, the wider facing sheet is attached and the edges are folded over and secured to the opposite facing sheet as the corrugated board is being produced.

Most machines for producing corrugated board, produce a continuous sheet much wider than the packaging blanks that are to be cut from the sheet. Thus, two or more strips of blanks are cut, continuously and lengthwise, from the sheet as the sheet is produced. Depending upon the size of the blank, the corrugated sheet, with both facing sheets attached, is discharged from the board making machine and, as it is discharged, the corrugated sheet is cut into strips of the desired width, and into blanks of the desired length. Even if the outside edges of the sheet are wrapped, as the board is produced, cutting the corrugated sheet into strips with both facing sheets attached, leaves the convolutions along the cut edges open. Because each blank has at least one cut edge when produced on such a machine, the convolutions at the cut edge of the blank are open. Reducing the width of the machine to produce a sheet the exact width of the blankto eliminate cutting the corrugated sheet into strips substantially increases cost and is not practical.

In the method and apparatus of the instant invention, a plurality of blank wide strips are simultaneously produced on a corrugated board machine with both of the edges of each strip closed and sealed by folding the edges of one facing sheet over the open ends of the core convolutions and securing the folded edge to the opposite facing sheet along the marginal edges of each strip. The corrugated core, with only one facing sheet adhesively secured to the core, is slit into two or more strips. The single-faced corrugated sheet may be produced from sheets of the desired width, the sheets may be trimmed before the single-faced corrugated sheet is formed, or the single-faced corrugated sheet may be trimmed to the desired width before the sheet is slit into two or more strips. The strips are spread apart a predetermined distance and are then adhesively secured to a wider, second facing sheet, or backer. The backer, intermediate the strips, is slit, folded around the open edges of the corrugated core at the edges of the strips and adhesively secured to the face of the opposite facing sheet along both marginal edges of each strip. Thus, two, or more, continuously fed strips of single-faced, corrugated board, are spaced transversely of the direction in which the strips are being fed, and adhesively secured to a wider second facing sheet, or backer. To accomplish this, the strips, after the single-faced corrugated sheet is slit, are spread apart and guided into accurate spaced alignment of the second facin sheet or backer. a

The paper sheet from which the corrugated core is formed, and the facing sheets, may vary across their respective Widths, in thickness, or caliper, and in moisture content depending on how the paper was made, how the paper rolls were stored and the storage conditions. These variations, together with variations in the corrugating machine, and other variables, vary the tautness of the s1ngle-faced corrugated sheet produced by the corrugation machine. Thus, at one edge of the single-faced corrugated sheet, the sheet may be relatively taut while, at the other edge of the sheet, the sheet may be relatively loose. This variation in tautness across the width of the sheet, when the s1ngle-faced sheet is cut into strips before the second facing sheet, or backer, is applied, lengthens the strip cut at the looser or less taut edge of the sheet, relative to the strip cut at the taut edge.

In the method and apparatus of the instant invention it has been discovered that, by pulling the sheets through the apparatus and applying a brake, or drag, to each strip, after the single-faced sheet is cut into a plurality of strips, the strips can be spread, guided and adhesively secured to the second facing sheet, or backer. Each strip, after it passes the brake, or drag, is under tension While it is being guided and when it is fed into contact with the second facing sheet, or backer. This results in an accumulation in strip length, in the strip cut at the looser or less taut edge of the sheet, which accumulation occurs between the strip cutting knife and the brake, or drag. During the initial operation of the machine, the accumulation is relatively small and does not interfere with the operation of the machine. However, as the machine continues to operate, the accumulation increases and, in time, would interfere with the operation of the machine and the proper spacing, guiding and adhesively securing of the strips to the second facing sheet, or backer. To prevent this interference, in the method and apparatus of the instant invention, the knife, or knives, cutting the single-faced sheet into strips are raised and the single-faced sheet, in full width, is passed through the apparatus. When this is done, the excess length in the strip, cut at the looser or less taut edge of the sheet, is taken up in the apparatus and the knives can then be relowered and a plurality of strips can again be simultaneously produced. While the knives are raised, which is usually only for a short interval, for example, while 3 or 4 ft. of the single-faced sheet material passes, uncut, through the knives, a full width sheet passes through the machine. So that this can be done, in the apparatus of the instant invention, the guides for spacing the cut strips and the guides for folding and wrapping the edges of the second sheet, or backer, around the open ends of the convo-lutions of the corrugated core, at the cut edges, are arranged so that the full width sheet can pass through the apparatus.

The invention will be better understood from the following description and appended drawings in which:

FIG. 1 is a top plan view of a portion of the apparatus of the instant invention showing the knife, brakes, or drags, feeder drums and the corrugated single-faced sheet and strips as fed therethrough;

FIG. 2 is a side elevational view of the apparatus of FIG. 1, taken at 2-2, FIG. 1;

FIG. 3 is a top plan view of an additional portion of the apparatus of the instant invention showing the feeding, drying and embossing apparatus, adhesive applicator and drier and the corrugated single-faced strips as fed therethrough and the second facing sheet, or backer, is applied and the double-faced strips are embossed and second facing sheet is cut;

FIG. 4 is a side elevation view of the apparatus of FIG. 3, taken at 3-3, FIG. 3;

FIG. 5 is a top plan view of still an additional portion of the apparatus showing the edge adhesive applicators, forming guides and the double-faced strips as fed therethrough and the edges folded;

FIG. 6 is a side elevational view of the apparatus of FIG. 5, taken at 6-6, FIG. 5;

FIG. 7 is an end view, taken in section at 7-7, FIG. 5; and

FIG. 8 is a perspective view, partly broken away, of the wrapped edge board produced in the method and apparatus of the instant invention.

In the instant invention, a single-faced corrugated sheet is formed in the conventional manner on a corrugated machine, not shown. In such machine, a sheet of paper is fed from a roll through the corrugated rollers of the corrugating machine, the sheet is corrugated and an adhesive is applied to the crowns at one side of the corrugated sheet. A first facing sheet is fed from a roll into contact with the adhesive bearing crowns and the adhesive is cured, attaching the first facing sheet to one side of the corrugated sheet. This is all done on a conventional, commercial corrugating machine with which the instant invention is not concerned other than in the single-faced corrugated sheet formed thereon.

In the illustrated embodiment, the single-faced corrugated sheet is cut into two strips, applied to a second liner and the edges of the second liner are folded around the edges of the strips to produce two strips of closed edge boards. It is understood, of course, that instead of cutting the single-faced sheet and second liner into two strips by a single knife, the sheets may be cut into three or more strips by a plurality of knives.

Referring now to the drawings, the apparatus of FIG. 1 includes platform 2, supported on legs 4, on frame 6 which in turn, is supported on vertical members 8. Guide 10 is mounted above platform 2 on vertical supports 12, 14. Knife 16, fixed to shaft 18, mounted at its opposite ends in bearings 20, 22 in knife frames 24, 26, is driven by motor 28, through sprockets 30, 32 and chain 34. Guide bars 36, 38 having, adjacent their opposite ends, respectively, guide collars 40, 42, 44, 46 are mounted at their opposite ends, in knife frames 24, 26, on opposite sides of knife 16. Knife 48 is mounted on the end of support 50 which, at its opposite end, is fixed to shaft 52, mounted, at its opposite ends, in frames 24, 26, handle 54, on shaft 52, being fixed to shaft 52 for lifting knife 48, for purposes later described. Spacer blade 56, pivotally mounted on support 58, is suspended above platform 2, and raised and lowered by cable 60.

Heater drum 62 and guide bars '64, 66, are mounted on stands 68, 70 on frame 6. Spacer guide 72 is fixed to the center of guide bar 64.

Crescent shaped guide 74 and guide bars 76, 78 are mounted, at their opposite ends, in stands 80, 82 on frame 6. Spacer guides 84, 86 are mounted, in fixed position, at the center of guide bar 76. Brakes 88, 90, of heavy fabric, such as canvas, or the like are fixed, at one of their ends to, bar 92 extending from, and fixed at, its opposite ends to stands 80, 82. Weight 92 is attached to the end of brake 88 and weight 94 is attached to the end of brake 90.

Referring now to FIGS. 3 and 4,-guide rolls 96, 98, 99, are fixed, at their opposite ends, to frames 100, 102. Adhesive applicator roll 104, with mating I011 106, driven from a source, not shown are mounted at their opposite ends in frames 100, 102, the lower end of roll 104 extending into adhesive tray 108, for purposes later described. Roll holds the corrugated strips in contact with applicator roll 104, for purposes later described. Heater roll 112 and guide rolls 114, 116, mounted at the opposite sides thereof, are mounted, at the opposite ends, in stands 100, 102.

Still referring to FIG. 4, the drier includes a frame having driven rollers 122, 124, driven from a power source, not shown, and tension rolls 126, 128, belt extends around roll 122, roll 130 and tension roll 132 and bent 134 extends around roll 125, tension roll 128 and a roll upstream of the machine, but not shown. Belts 130, 134 extend across the full width of the machine and, as will be later described, pull the single-faced corrugated sheet, the corrugated strips and the second facing sheet from the left to the right as viewed in FIGS. 3 and 4. Driven roll 140, driven from a source, not shown, is mounted on pedestals 142, 144 and rotatably cutting knife 146 is fixed to roll 140, for reasons described later. Embossing rolls 148, 150 are fixed to roll 140. Cutting knife 152 and embossing back up rolls 151 are fixed to shaft 154.

Referring now to FIGS. 5, 6, and 7, the edge forming apparatus, generally designated 160, includes outer edge stationary guides 162, 164., inner edge stationary guide 166, outer edge forming rollers 168, 170, 172, 174, 176 and 178, 180, 182, 184, 186 and inner edge forming rollers 188, 190, 192, 194, 196 and 198, 200, 202, 204, 206, all mounted on frame 210. As best shown in FIG. 7, the outer edge forming rolls are taller than the inner edge forming rolls and this is important in the apparatus and method of the instant invention, for reasons more apparent later.

Adhesive applicators 212, 214, 216, 218 are mounted on upwardly extending extensions 211, of frame 210. Weights 220, 222, 224 are fixed, respectively, to the ends of fabric strap 226, 228, 230 attached at their opposite ends to cross-member 232 of frame 210. Pinch rolls 2'40,

242 are mounted, at their opposite ends, in supports 244, 246 and, for purposes later explained, are driven from a source, not shown.

As shown in FIG. 8, the strips of corrugated board produced in the instant invention have a corrugated core, or center 250 to which is adhesively attached, at one side of the core, facing sheet 252. Facing sheet 254 is adhesive- 1y secured to the opposite side of core 250 with the edges of facing sheet 254 folded around the opposite, open ends of the core convolutions and adhesively scoured to the face of facing sheet 250 at 254A and 254B.

In the process of the instant invention, the corrugated core, having one facing sheet secured to one side, is cut into strips by a rotary knife, the strips are spaced apart and heated. Adhesive is applied to the crows of the exposed convolutions of the heated strips and the crowns are brought into contact with a wider facing sheet. The single-faced, corrugated core sheet is pulled through the rotary knife and the strips cut by the knife are pulled through the spacer guides, heater and adhesive applicator by pulling the strips after the strips are adhesively applied to the second facing sheet. This is accomplished, in the method and apparatus of the instant invention, by the driven belts 130, 134 of the drier.

Before start-up of the apparatus, the operator, with handle 54, lifts knife 48 away from the driven knife 16 to the position shown in phantom line in FIG. 2 and, with cable 60 lifts spacer blade 56. The single-faced corrugated sheet, with the single facing sheet up and the corrugated core down, is then threaded over guide 10, under guide 36, between guide collars 40, 42, over knife 16 and under guide 38, under guide bar 76, over crescent shaped guide 74, under guide bar 78, over guide bar 64, around heater drum 62, over guide bar 66 and guide roll 96, under guide roll 98, and between adhesive applicator roll 104 and roll 110. The single-faced corrugated sheet is then brought into contact with the second facing sheet and the singlefaced corrugated sheet and second sheet are fed into the drier between belts 130, 134. With the belts driven, the single-faced corrugated sheet is pulled through the apparatus of FIGS. 1 and 2 and through the adhesive applicator of FIGS. 3 and 4. The second facing sheet is applied and the sheet, with the second facing sheet applied is pulled through the drier of FIGS. 3 and 4 and is fed out of the drier into edge forming apparatus 160 of FIGS. 5 and 6 to pinch rolls 240, 242, driven at the same approximate speed as the driven belts. Pinch rolls 240, 242 pull the sheet from the drier and through edge forming apparatus 160. In the start-up of the apparatus, a full width, uncut, sheet is discharged from pinch rolls 240, 242.

With knife 48 and spacer blade 56 lifted, the full width sheet is guided, at its edges, between guide collars 40, 42, 44, 46 and outer edge forming rollers 168, 170, 172, 164, 176 and 178, 180, 182, 184, 186. The center of the sheet passes over spacer guides 84, 86, 72, inner edge stationary guide 166, and inner edge forming rollers 188, 190, 192, 194, 196 and 198, 200, 202, 204, 206. In passing between guide collars 40, 42, 44, 46 and outer edge forming rollers 168, 170, 172, 174, 176- and 178, 180, 182, 184, 186, the full width single-faced corrugated sheet is aligned with, the apparatus. Spacer guides 84, 86, 72, inner edge spacing guide 166 and edge forming rollers 188, 190, 192, 194, 196 and 198, 200, 202, 204, 206, under the center of the full width sheet, do not interfere with sheet alignment.

The full width sheet, pulled and fed through the apparatus by drier belts 130, 134 and pinch rolls 240, 242, readily aligns itself with the apparatus. When the full width sheet is aligned, shaft 52 is rotated, with handle 54, to bring knife 48 into operating engagement with driven knife 16, driven at a speed slightly faster than the feed speed of the single facing sheet. Spacer plate 56 is lowered.

As the single-faced sheet is pulled through operationally engaged knives 48, 16, the single-faced sheet is cut into strips and the strips are spread, or spaced by spacer guides 84, 86, 72. The spaced, single-faced strips are heated, on heater roll 62, adhesive is applied to the convolution crowns by roller 104 and the space strips are brought into contact with the second facing sheet and the second facing sheet and strips enter the drier between belts 130, 134. When the second facing sheet, with the strips spaced and adhesively secured, emerges from the drier, roller 140,

knives 146, 152, slit the second facing sheet intermediate the edges of the spaced strips. To start the strips though edge forming apparatus 160 the strips, with the second facing sheet slit, are initially pushed down, manually by the operator. As the strips enter edge forming apparatus 160, the opposite outer edges of the strips pass through stationary guides 162, 164, 166 and engage the lower portions of outer edge forming rollers 168, 170, 172, 174, 176 and 188, 190, 192, 194, 196, and 178, 180, 182, 184, 186 and 198, 200, 202, 204, 206, respectively. Stationary guides 162, 164, 166 turn the extending edges of the second facing sheet upwardly and the edge forming rollers fold the upwardly extending edges upwardly and inwardly over the outer surface of the first facing sheet where the fold edges are adhesively secured with the adhesive already applied to the first facing sheet and extending edges of the second facing sheet by applicators 212, 214, 216, 218.

The cut and spaced single-faced sheets are pulled through and fed onto the wider second facing sheet by drier belts 130, 134. Brakes '88, 90, with weights 92, 94, maintain a substantially uniform tension on each of the strips between brakes 88, and dried belts 130, 134. Because of the variation in tautness across the width of the single-faced sheet, the effective length of the strips, between knives 48, 16 and brakes 88, 90 will vary, one of the strips becoming longer than the other as operation of the apparatus and production of the strips continues. Thus, between knives 48, 16 and brakes 88, 90, a loop forms in one strip which, after the machine has been run and strips have been produced for a length of time, accumulates and, if allowed to continue to accumulate, will interfere with the operation of the apparatus.

Before such excess accumulation occurs in the apparatus of the instant invention, knife 48 is lifted by the machine operator by rotating shaft 52 with handle 54. Spacer plate 56 is lifted by cable 60. This is done without stopping the machine. A full width sheet then passes through knives 48, 16, over guides, 84, 8'6, 72, through the drier and through edge forming apparatus 160.

As the full width sheet passes knives 48, 16 and brakes 88, 90, the accumulation, or slack, in the loop of the longer strip is taken up and absorbed and passes between the guides, the adhesive applicator, the drier, the embossing rolls and the edge forming apparatus without interference. Usually, knife 48 can be lifted and the loop accumulation in the longer strip can be taken up and absorbed in the apparatus while only three or four feet of full width corrugated strip passes between knives 48 16. .As soon as the loop is absorbed, knife 48 is again lowered and continuous strips are again produced. This is all done without stopping or shutting down the machine.

Once the machine is started up, it can be run continuously. As the various rolls of paper sheets fed into the machine to make up the corrugated core and the facing sheets are used up, the beginning of a sheet from the following roll may be lapped with and secured to the end of the sheet of the preceding roll, in the conventional manner, while operation of the apparatus continues. Where the beginning of the sheet of one roll is lapped to the end of the sheet of a preceding roll and where a full width sheet is produced by the lifting of knife 48, sections so produced are trimmed out of the produced strips and scrapped.

The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

We claim:

1. The method of making strips of corrugated core paperboard in which the opposite edges of one facing sheet are wrapped around the edges of the corrugated core at the opposite edges of the strips and adhesively secured to the facing sheet from a single-faced corrugated sheet cut into strips and laterally spaced and adhesively secured to a wider, second facing sheet having edges extending outwardly beyond the outer edges of the laterally spaced strips secured thereto, the steps comprising, with a single pulling force applied with said laterally spaced strips in engagement with said wider, second facing sheet, pulling the single-faced corrugated sheet and, While pulling said corrugated sheet, cutting said sheet longitudinally into strips, applying a drag to each of said strips to tension said strips, said drag being applied intermediate said cutting step and a subsequent spacing step, laterally spacing each of said strips, guiding said laterally spaced strips, applying an adhesive to the crowns of the convolutions of said corrugated core and engaging said laterally spaced, guided strips with said adhesive with the wider, second facing sheet, curing said adhesive, cutting said wider, second facing sheet intermediate said space strips leaving an edge of said second facing sheet projecting outwardly beyound said corrugated core at the opposite edge of said strips, applying an adhesive to said projecting edges and the edges of the first facing sheet, folding said projecting edges of said second facing sheet around the ends of the corrugated edges of said strips and into engagement with the face of the first facing sheet, curing said adhesive to secure said folded projecting edges of said second facing sheet to said first facing sheet, periodically interrupting said cutting and spacing steps While continuing said pulling, said interruption being maintained for a time interval suflicient to permit any excess length in one or more of said cut strips to be absorbed, and then resuming said cutting and spacing steps.

References Cited UNITED STATES PATENTS 3/1967 Martin, SR 156271X 3/1969 Rein 156202 SAMUEL W. ENGLE, Primary Examiner UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.

Inventor(s) Robert L Washburn et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 1, line 69, "edges" should read edge 2, line 15, "edges" should read edge 47, "of" should read on 4, line 7, insert comma after "which";

48, "bent" should read belt 5, line 11, "250" should read 252 l4, "spaced" should read spread l5, "crows" should read crowns 44-45, insert comma after "applied";

54, "164" should read 174 61, after "with" insert and adhesively secured to, the second facing sheet and is aligned 6, line 9, "though" should read through 29, "dried" should read drier 7, line 25, "space" should read spaced Signed and sealed this 7th day of September 1971 (SEAL) Attest:

EDWARD M.FLETCHER JR. 7 Attesting Officer ROBLRI GOT'ISCHALR Acting Commissioner of Patents FORM PO-105O (10-69) USCOMM-OC 5O376-P69 U 5 GOVERNMENT PRINYING OFFICI; 1969 0-365-334 

